The field of the present invention is surveying apparatuses for measuring layout of buildings. A surveying apparatus necessarily performs a geometric instrument function and, depending on the underlying technology, can perform an optical measuring function.
Currently, buildings are surveyed most of the time using simple measuring tools, such as a mechanical tape measure or a laser “tape measure”—a laser distance meter. U.S. Pat. No. 7,640,214 and U.S. patent application Ser. No. 10/724,259 describe systems that add angle measuring capabilities to laser distance meters to increase speed and efficiency with which the measurements can be done. Nevertheless, a workflow using such tools is very slow and a surveyor needs to spend a considerable amount of time on-site taking measurements.
It would be advantageous to be able to capture surveying data on-site quickly and to allow post-processing and analysis of data and creation of floor plans to be carried out elsewhere. In addition, it would be advantageous to capture image data for the purpose of documenting a site in a fashion that would allow the image data to be correlated with floor plans, for example, by recording an accurate location and direction from which an image was taken. Such instruments and a combination of measurement and image data can find uses in several industries. As an example, in a real estate industry or in an insurance industry such an indoor surveying apparatus can be used for capturing floor plans and images of a property that can be subsequently displayed in a virtual tour. As a further example, in forensic sciences such an indoor surveying apparatus can be used for documenting a crime scene and can provide a capability to make subsequent measurements using captured floor plan and image data. As yet another example, in a construction industry such an indoor surveying apparatus can be used to capture structural elements of a building at various construction stages, such as capturing a house frame with embedded wiring before drywall gets installed.
Currently, the only commercially available technology for capturing correlated dimensioned layout and image data is a 3D laser scanner that includes a camera for capturing image or texture data that can be overlaid on a 3D point cloud. Several manufacturers offer such instruments that have high accuracy and long range, which makes them suitable for both indoor and outdoor applications requiring high resolution. The software provided with the 3D laser scanners typically allows extracting 2D slices from 3D point cloud that can be used for drawing floor plans. While such instruments are versatile, the amount of data they capture is excessive for the usage scenarios listed above, the time required to capture a 3D scan of a room is still on the order of few minutes, and the cost of such instruments is prohibitively expensive for the mentioned uses.
Currently, an active research topic in the field of robotics at universities is unmanned ground and aerial vehicles (robots) that are capable of mapping and modeling their environment. Such robots often have a 2D scanning laser range finder and one or more cameras for capturing video or still images. In some robots, the cameras are calibrated and aligned with laser range finders. During navigation such robots use Simultaneous Localization And Mapping (SLAM) algorithms to dynamically build a 2D point cloud map of their environment using the laser range finder data and compute their position and orientation on that map. See P. Biber et al. “3D Modeling of Indoor Environments by a Mobile Robot with a Laser Scanner and Panoramic Camera” in Proc. Int. Conf. on Intelligent Robots and Systems (2004) and S. Kohlbrecher et el. “A Flexible and Scalable SLAM System with Full 3D Motion Estimation” in Proc. IEEE Int. Symp. on Safety, Security and Rescue Robotics (2011). These and all other referenced publications are incorporated herein by reference in their entirety. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Since the robots described above are not designed for the indoor surveying usage scenarios such as those listed earlier, their use for such purposes would be complicated for an average user and too time-consuming. In addition, they do not provide means for drawing floor plans and creating virtual tours.
Therefore, there remains a considerable need for an indoor surveying apparatus that can measure layout and capture images correlated with the measurement data, perform these tasks quickly, allow off-line processing and analysis of data, be easy to use, and have reasonable cost.